To completely comprehend the background of the invention the following definitions should be considered.
A dosimeter is a device for measuring ionizing radiation. It may be active, as in a remmeter or other Radiac or it may be passive such as film, TLD or personnel dosimeter.
Ionizing radiation is radiation that effects personnel by ionization. This includes radiation which has no charge but produces ions in the body, for example ions produced by neutrons and gamma rays.
In the past the Navy has used several calibrators and radiation source storage containers. Until the development and wide use of the instant invention which shall be called calibrator AN/UDM-10 the prior art device in use was about three feet by three feet by four feet in size and was filled with approximately 2000 pounds of wax.
It was very difficult to load and unload from Navy ships, sometimes a special port had to be constructed in the side of a ship to accommodate the device.
In addition, this device used a 5 Curie Plutonium Beryllium radiation source, in order to emit sufficient intensity to serve as a calibration source.
In addition, for shipment, the radioactive source had to be transferred to another container. This required two containers and exposed personnel to direct radiation from the unshielded source during transfer.
The invention claimed in this application clearly presents many advantages and advancements over the prior art calibration device.
Therefore, it is one object of this invention to provide a transportable radiation source container that may be used as both a calibration device and a shipping container.
It is another object of this invention to provide a radiation calibration device that can be manually loaded on Navy ships without the use of a crane.
It is a still further object of this invention to provide a portable calibration device that contains a non hazardous filler made of a neutron attenuation material that may be extended by water.
It is another object of this invention to provide a calibration device that has means for storage of radiation source material at the center of the small portable radiation calibration device and has a built in means for moving the source to various calibration positions within the device.
It is a still further object of the invention to provide a calibration device that will allow mounting of the dosimeter directly on the top of the calibration device.
It is a still further object of the invention to provide a calibration device that has a relatively high intensity compared with prior art calibrators with similar small radiation sources and similar low personnel radiation exposure requirements.